LT3507IUHF-PBF datasheet(12/28 Pages) LINER

部件名	LT3507IUHF-PBF

功能描述	Triple Monolithic Step-Down Regulator with LDO

Download	28 Pages

Scroll/Zoom	100%

制造商	LINER [Linear Technology]

网页	http://www.linear.com

标志

12 / 28 page

LT3507

12

3507f

Select an inductor greater than LMIN that keeps the ripple

current below 30% of ILIM.

The inductor’s RMS current rating must be greater than the

maximum load current and its saturation current should

be greater than ILPK. For highest efﬁciency, the series

resistance (DCR) should be less than 0.1Ω. Table 1 lists

several vendors and types that are suitable.

Table 1. Inductors

PART NUMBER

VALUE

(μH)

ISAT

(A)

DCR

(Ω)

HEIGHT

(mm)

Sumida

CDC5D23-2R2

2.2

2.16

0.030

2.5

CDRH5D28-2R6

2.6

2.60

0.013

3.0

CDRH6D26-5R6

5.6

2.00

0.027

2.8

CDH113-100

10

2.00

0.047

3.7

Coilcraft

DO1606T-152

1.5

2.10

0.060

2.0

LPS6225-222ML

2.2

4.00

0.045

2.4

DO1608C-332

3.3

2.00

0.080

2.9

MSS6132-472ML

4.7

2.60

0.056

3.2

DO1813P-682HC

6.8

2.20

0.080

5.0

Cooper

SD414-2R2

2.2

2.73

0.061

1.35

DRA73-6R8-R

6.8

2.96

0.041

3.55

UP1B-100

10

1.90

0.111

5.0

Toko

(D62F)847FY-2R4M

2.4

2.5

0.037

2.7

(D73LF)817FY-2R2M

2.2

2.7

0.03

3.0

This analysis is valid for continuous mode operation

(IOUT > ILIM/2). For details of maximum output current in

discontinuous mode operation, see Linear Technology’s

Application Note AN44. Finally, for duty cycles greater

than 50% (VOUT/VIN > 0.5), a minimum inductance is

required to avoid subharmonic oscillations. This minimum

inductance is:

SW1:LMIN = VOUT + VF

()•

0.45

fSW

SW2, SW3:LMIN = VOUT + VF

()•

0.9

fSW

with LMIN in μH and fSW in MHz.

Output Capacitor Selection

The output capacitor ﬁlters the inductor current to generate

an output with low voltage ripple. It also stores energy in

order to satisfy transient loads and stabilize the LT3507’s

control loop. Because the LT3507 operates at a high

frequency, minimal output capacitance is necessary. In

addition, the control loop operates well with or without

the presence of output capacitor series resistance (ESR).

Ceramic capacitors, which achieve very low output ripple

and small circuit size, are therefore an option.

You can estimate output ripple with the following

equations:

VRIPPLE =

ΔIL

8• f • COUT

for ceramic capacitors

and

VRIPPLE = ΔIL •ESR for electrolytic capacitors

(tantalum and aluminum)

where ΔIL is the peak-to-peak ripple current in the inductor.

The RMS content of this ripple is very low so the RMS

current rating of the output capacitor is usually not of

concern. It can be estimated with the formula:

IC(RMS) =

ΔIL

12

Another constraint on the output capacitor is that it must

have greater energy storage than the inductor; if the stored

energy in the inductor transfers to the output, the resulting

voltage step should be small compared to the regulation

voltage. For a 5% overshoot, this requirement indicates:

COUT >10 •L •

ILIM

VOUT

2

ThelowESRandsmallsizeofceramiccapacitorsmakethem

the preferred type for LT3507 applications. Not all ceramic

capacitors are the same, however. Many of the higher value

capacitors use poor dielectrics with high temperature and

voltage coefﬁcients. In particular, Y5V and Z5U types lose

a large fraction of their capacitance with applied voltage

and at temperature extremes. Because loop stability and

transient response depend on the value of COUT, this loss

may be unacceptable. Use X7R and X5R types.

APPLICATIONS INFORMATION

类似零件编号 - LT3507IUHF-PBF

制造商	部件名	数据表	功能描述
Linear Integrated Syste...	LT3507IUHF	280Kb / 28P	Triple Monolithic Step-Down Regulator with LDO

More results

类似说明 - LT3507IUHF-PBF

制造商	部件名	数据表	功能描述
Linear Technology	LT3507A	384Kb / 8P	Triple Monolithic Step-Down Regulator with LDO
Linear Dimensions Semic...	LT3507EUHFTRPBF	307Kb / 28P	Triple Monolithic Step-Down Regulator with LDO
Linear Technology	LT3507	307Kb / 28P	Triple Monolithic Step-Down Regulator with LDO
Linear Technology	LT3507A	381Kb / 28P	Triple Monolithic Step-Down Regulator with LDO
Linear Integrated Syste...	LT3507EUHF	280Kb / 28P	Triple Monolithic Step-Down Regulator with LDO
STMicroelectronics	L5964	369Kb / 16P	Automotive monolithic dual step-down switching regulator with LDO February 2022 Rev 1
Linear Technology	LT8601	1Mb / 26P	42V Triple Monolithic Synchronous Step-Down Regulator
Intersil Corporation	EL7536	430Kb / 8P	Monolithic 1A Step-Down Regulator
Renesas Technology Corp	EL7535	505Kb / 10P	Monolithic 350mA Step-Down Regulator
Intersil Corporation	EL7536	186Kb / 9P	Monolithic 1A Step-Down Regulator